Capacitors located across amplifier gain stages (whether inherent in a given topology or discretely placed) cause the amplifiers to suffer from what is known as the Miller effect. The Miller effect multiplies the given capacitance value by the value of gain across the stage; thus resulting in a larger effective capacitance as seen looking into the amplifier input. This capacitance has the effect of lowering the pole frequency at the gain stage input due to the higher capacitance. The result is a lower bandwidth for the amplification stage.